The control of the cell cycle with particular emphasis on the G1/S transition
Tumour development occurs to a large extent because of dysregulation of the cell cycle. Of particular importance are defects occurring in the G1 phase. The reason why G1 is critical is because of the influence of several signals (external signals as well as cyclins and cdks) on this stage. The G1 ph...
| Autor principal: | |
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| Formato: | First cycle, G2E |
| Lenguaje: | sueco Inglés |
| Publicado: |
2014
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| Acceso en línea: | https://stud.epsilon.slu.se/6635/ |
| _version_ | 1855571045928402944 |
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| author | Andersson, Erika |
| author_browse | Andersson, Erika |
| author_facet | Andersson, Erika |
| author_sort | Andersson, Erika |
| collection | Epsilon Archive for Student Projects |
| description | Tumour development occurs to a large extent because of dysregulation of the cell cycle. Of particular importance are defects occurring in the G1 phase. The reason why G1 is critical is because of the influence of several signals (external signals as well as cyclins and cdks) on this stage. The G1 phase can be divided into two parts, G1pm and G1ps. Each part has its “own” restriction point which needs to be passed in order to progress to S phase. The first restriction point, R1, is growth-factor dependent and decides if the cell progresses to S phase and hence also controls the chromosomal cell cycle i.e. DNA-replication and mitosis. The second restriction point, R2, located in G1ps is nutrient dependent and decides when the cell will progress to S phase. By doing so it controls that the daughter cells are the same size before they enter S phase. Transformed cells need to overcome both R1 and R2 in order to induce tumour development.
Transition from G1 to S is driven by genes that encode several proteins that regulate downstreaming signals. Ras is one of the most important proteins that not only regulate one downstream pathway but several overlapping pathways.
Even though the main emphasis is on the G1 phase other phases can also affect the transformation process. For instance unsolved and incompletely replicated DNA in the S phase without a cell cycle stop before M phase is an area that has aroused recent interest.
There are several issues that need further investigation. The findings of novel suppressor genes that inhibit oncogene expression and consequently induce apoptosis and cell senescence may contribute to the solving of the cancer riddle. |
| format | First cycle, G2E |
| id | RepoSLU6635 |
| institution | Swedish University of Agricultural Sciences |
| language | Swedish Inglés |
| publishDate | 2014 |
| publishDateSort | 2014 |
| record_format | eprints |
| spelling | RepoSLU66352014-09-12T13:16:17Z https://stud.epsilon.slu.se/6635/ The control of the cell cycle with particular emphasis on the G1/S transition Andersson, Erika Animal physiology and biochemistry Human medicine, health, and safety Tumour development occurs to a large extent because of dysregulation of the cell cycle. Of particular importance are defects occurring in the G1 phase. The reason why G1 is critical is because of the influence of several signals (external signals as well as cyclins and cdks) on this stage. The G1 phase can be divided into two parts, G1pm and G1ps. Each part has its “own” restriction point which needs to be passed in order to progress to S phase. The first restriction point, R1, is growth-factor dependent and decides if the cell progresses to S phase and hence also controls the chromosomal cell cycle i.e. DNA-replication and mitosis. The second restriction point, R2, located in G1ps is nutrient dependent and decides when the cell will progress to S phase. By doing so it controls that the daughter cells are the same size before they enter S phase. Transformed cells need to overcome both R1 and R2 in order to induce tumour development. Transition from G1 to S is driven by genes that encode several proteins that regulate downstreaming signals. Ras is one of the most important proteins that not only regulate one downstream pathway but several overlapping pathways. Even though the main emphasis is on the G1 phase other phases can also affect the transformation process. For instance unsolved and incompletely replicated DNA in the S phase without a cell cycle stop before M phase is an area that has aroused recent interest. There are several issues that need further investigation. The findings of novel suppressor genes that inhibit oncogene expression and consequently induce apoptosis and cell senescence may contribute to the solving of the cancer riddle. En viktig orsak till tumörers uppkomst står att finna i en defekt hos cellcykelns reglering. En felaktig reglering av cellcykelns G1-fas tros vara en betydande orsak. Anledningen till att G1-fasen är extra känslig beror på att den styrs av många olika signaler på olika nivåer (såväl yttre faktorer som cykliner och cdks). I denna del av cellcykeln fattas viktiga beslut. G1-fasen kan delas upp i två delar, G1pm och G1ps. De innehåller varsin restriktionspunkt som måste passeras för att cellerna ska kunna gå in i S-fasen. Den första restriktionspunkten, R1, är beroende av tillväxtfaktorer och där bestäms om en cell ska fortsätta till S-fasen. Den kontrollerar således den cellcykel som innefattar DNA-replikation och mitos. Den andra restriktionspunkten, R2, som ligger i G1ps är bl a beroende av mängden näring och bestämmer när en cell ska gå vidare in i S-fasen. Genom denna reglering justeras cellernas storlek så att dottercellerna är lika stora när de ska gå in i S-fasen. Tumörutveckling kan ske först när de transformerande cellerna har kunnat ta sig förbi både R1 och R2. G1-S gener kodar för flertalet proteiner som reglerar kaskadsignaler nedströms ner till kärnan där de slutligen kan verka som t.ex. transkriptionsfaktorer. Ras är ett av de viktigaste proteinerna som inte bara reglerar en utan flera intracellulära signalvägar som innehåller överlappande signaler. Dessa överlappande signaler är ett av de viktigaste kvarvarande vita fälten inom cancerforskningen. Men de andra faserna i cellcykeln kan också påverka tumörutvecklingen. Ett exempel som uppmärksammats på senare år är oupplösta och ofullständigt replikerade delar av arvsmassan i S-fasen som fortsätter vidare till M-fasen utan att cellen stoppas. Det finns ännu många frågetecken som måste rätas ut. Sålunda arbetas det intensivt på att se hur onkogener kan tystas och därmed få defekta celler att gå i apoptos eller åldras. Dessa forskningslinjer kan innebära revolutionerande framsteg på vägen mot lösningen av cancerns gåta. 2014-04-15 First cycle, G2E NonPeerReviewed application/pdf sv https://stud.epsilon.slu.se/6635/11/andersson_e_140905.pdf Andersson, Erika, 2014. The control of the cell cycle with particular emphasis on the G1/S transition. First cycle, G2E. Uppsala: (VH) > Dept. of Biomedical Sciences and Veterinary Public Health (until 231231) <https://stud.epsilon.slu.se/view/divisions/OID-713.html> urn:nbn:se:slu:epsilon-s-3729 eng |
| spellingShingle | Animal physiology and biochemistry Human medicine, health, and safety Andersson, Erika The control of the cell cycle with particular emphasis on the G1/S transition |
| title | The control of the cell cycle with particular emphasis on the G1/S transition |
| title_full | The control of the cell cycle with particular emphasis on the G1/S transition |
| title_fullStr | The control of the cell cycle with particular emphasis on the G1/S transition |
| title_full_unstemmed | The control of the cell cycle with particular emphasis on the G1/S transition |
| title_short | The control of the cell cycle with particular emphasis on the G1/S transition |
| title_sort | control of the cell cycle with particular emphasis on the g1/s transition |
| topic | Animal physiology and biochemistry Human medicine, health, and safety |
| url | https://stud.epsilon.slu.se/6635/ https://stud.epsilon.slu.se/6635/ |